COMPOSITION THEREOF

BACKGROUND

[0001] Previously, carbonaceous articles, such as carbon fibers, have been produced primarily from polyacrylonitrile (PAN), pitch, or cellulose precursors. The process for making carbonaceous articles begins by forming a fabricated article, such as a fiber or a film, from the precursor. Precursors may be formed into fabricated articles using standard techniques for forming or molding polymers. The fabricated article is subsequently stabilized to allow the fabricated article to substantially retain shape during the subsequent heat-processing steps; without being limited by theory, such stabilization typically involves a combination of oxidation and heat and generally results in dehydrogenation, ring formation, oxidation and crosslinking of the precursor which defines the fabricated article. The stabilized fabricated article is then converted into a carbonaceous article by heating the stabilized fabricated article in an inert atmosphere. While the general steps for producing a carbonaceous article are the same for the variety of precursors, the details of those steps vary widely depending on the chemical makeup of the selected precursor.

[0002] Polyolefins have been investigated as an alternative precursor for carbonaceous articles, but a suitable and economically viable preparation process has proven elusive. Of particular interest is identifying an economical process for preparing stabilized articles from polyolefin precursors, such as stabilized articles which are suitable for subsequent processing to form carbonaceous articles. For example, maximizing mass retention during the stabilization and carbonization steps are of interest.

SUMMARY OF THE INVENTION

[0003] A method for preparing an article comprising: providing an olefin resin; melt blending the olefin resin with a treating agent to provide a treated olefin resin, the treating agent comprising an inorganic salt comprising a nitrogen-containing ion and a phosphorous- containing ion; forming a fabricated article from the treated olefin resin; crosslinking the fabricated article; and stabilizing the fabricated article by air oxidation.

[0004] A stabilized polyolefin article comprising an empirical formula, CHWNXPYOZ, where: 0.45≤ W≤ 0.85; 0.01≤ X≤ 0.035; 0.0005 < Y < 0.035; and 0.3≤ Z≤ 0.4.

[0005] A carbonized polyolefin article comprising an empirical formula, CNXPY, where: 0.005≤ X≤ 0.02 ; and 0.005 < Y < 0.025. DETAILED DESCRIPTION

[0006] Unless otherwise indicated, numeric ranges, for instance "from 2 to 10," are inclusive of the numbers defining the range (e.g., 2 and 10).

[0007] Unless otherwise indicated, ratios, percentages, parts, and the like are by weight.

[0008] Unless otherwise indicated, the crosslinkable functional group content for a polyolefin resin is characterized by the mol% crosslinkable functional groups, which is calculated as the number of mols of crosslinkable functional groups divided by the total number of mols of monomer units contained in the polyolefin.

[0009] Unless otherwise indicated, "monomer" refers to a molecule which can undergo polymerization, thereby contributing constitutional units to the essential structure of a macromolecule, for example, a polyolefin.

[0010] Unless otherwise indicated, "alkene" refers to CI to CIO alkenes.

[0011] Unless otherwise indicated, "alkyne" refers to CI to CIO alkynes.

[0012] In one aspect, the present disclosure describes a process for producing a stabilized fabricated article from a polyolefin resin. In one aspect, the present disclosure describes a process for producing a carbonaceous fabricated article from a polyolefin resin. Unless stated otherwise, any method or process steps described herein may be performed in any order. Polyolefins are a class of polymers produced from one or more olefin monomer. The polymers described herein may be formed from one or more types of monomers.

Polyethylene is the preferred polyolefin resin, but other polyolefin resins may be substituted. For example, a polyolefin produced from ethylene, propylene, or other alpha- olefin (for instance, 1-butene, 1-hexene, 1-octene), or a combination thereof, is also suitable. The polyolefins described herein are typically provided in resin form, subdivided into pellets or granules of a convenient size for further melt or solution processing.

[0013] The polyolefin resin is treated with a treating agent to provide a treated olefin resin. In one instance, the treating agent is nitrogen and phosphorous containing compound. In one instance, the treating agent is an inorganic salt comprising a nitrogen-containing ion and a phosphorous-containing ion. An exemplary example of a suitable treating agent is ammonium polyphosphate. Other examples of treating agents include phosphate amides, nitrogen containing phosphonic acids and their esters, nitrogen containing phosphinic acids and their esters, phosphine imides, phosphonamidate, phosphonamide, phosphinamide, phophoramidite, phosphoramidate, phosphorodiamidite, phosphorodiamidate,

phosphoramide, phosphinimide, and phosphazene. The melt phase of the polyolefin resin is defined as a condition where the polyolefin resin is suitable for forming into a fabricated article. In one instance, the melt phase is achieved by heating the resin to a temperature range where the solid resin transitions to a liquid, which temperature range will vary depending on the composition of the selected polyolefin resin, as is known in the art. In one instance, the treating agent is added to the melt phase resin. In another instance, the treating agent is introduced to the resin during the fabrication process. In another instance, the treating agent and the resin are dry blended prior to forming a melt phase; for example, the treating agent can be introduced as a masterbatch or neat. The polyolefin is treated with the treating agent such that either or both of the phosphorous or nitrogen is contained in the fabricated article following fabrication. Any suitable treating agent which deposits either or both of phosphorous or nitrogen in the fabricated article may be used.

[0014] The treated olefin resin is processed to form a fabricated article. A fabricated article is an article which has been fabricated from the polyolefin resin. The fabricated article is formed using known polyolefin fabrication techniques, for example, melt or solution spinning to form fibers, film extrusion or film casting or a blown film process to form films, die extrusion or injection molding or compression molding to form more complex shapes, or solution casting. The fabrication technique is selected according to the desired geometry of the target carbonaceous article, and the desired physical properties of the same. For example, where the desired carbonaceous article is a carbon fiber, fiber spinning is a suitable fabrication technique. As another example, where the desired carbonaceous article is a carbon film, compression molding is a suitable fabrication technique.

[0015] The fabricated articles described herein are subjected to a crosslinking step. A variety of methods for crosslinking polyolefins are known. In one instance, the fabricated articles are crosslinked by irradiation, such as by electron beam processing. Other crosslinking methods are suitable, for example, ultraviolet irradiation and gamma irradiation. In some instances, an initiator, such as benzophenone, may be used in conjunction with the irradiation to initiate crosslinking. In one instance, the polyolefin resins have been modified to include crosslinkable functional groups which are suitable for reacting to crosslink the polyolefin resin. Where the polyolefin resin includes crosslinkable functional groups, crosslinking may be initiated by known methods, including use of a chemical crosslinking agent, by heat, by steam, or other suitable method. In one instance, copolymers are suitable to provide a polyolefin resin having crosslinkable functional groups where one or more alpha-olefins have been copolymerized with another monomer containing a group suitable for serving as a crosslinkable functional group, for example, dienes, carbon monoxide, glycidyl methacrylate, acrylic acid, vinyl acetate, maleic anhydride, or vinyl trimethoxy silane (VTMS) are among the monomers suitable for being copolymerized with the alpha-olefin. Further, the polyolefin resin having crosslinkable functional groups may also be produced from a poly(alpha-olefin) which has been modified by grafting a functional group moiety onto the base polyolefin, wherein the functional group is selected based on its ability to subsequently enable crosslinking of the given polyolefin. For example, grafting of this type may be carried out by use of free radical initiators (such as peroxides) and vinyl monomers (such as VTMS, dienes, vinyl acetate, acrylic acid, methacrylic acid, acrylic and methacrylic esters such as glycidyl methacrylate and methacryloxypropyl trimethoxysilane, allyl amine, p-aminostyrene, dimethylaminoethyl methacrylate) or via azido-functionalized molecules (such as 4-[2- (trimethoxysilyl)ethyl)]benzenesulfonyl azide). Polyolefin resins having crosslinkable functional groups may be produced from a polyolefin resin, or may be purchased commercially. Examples of commercially available polyolefin resins having crosslinkable functional groups include SI-LINK sold by The Dow Chemical Company, PRIMACOR sold by The Dow Chemical Company, EVAL resins sold by Kuraray, and LOTADER AX8840 sold by Arkema.

[0016] As noted above, at least a portion of the polyolefin is crosslinked to yield a crosslinked fabricated article. In some embodiments, crosslinking is carried out via chemical crosslinking. Thus, in some embodiments, the crosslinked fabricated article is a fabricated article which has been treated with one or more chemical agents to crosslink the crosslinkable functional groups of the polyolefin resin having crosslinkable functional groups. Such chemical agent functions to initiate the formation of intramolecular chemical bonds between the crosslinkable functional groups or reacts with the crosslinkable functional groups to form intramolecular chemical bonds, as is known in the art. Chemical crosslinking causes the crosslinkable functional groups to react to form new bonds, forming linkages between the various polymer chains which define the polyolefin resin having crosslinkable functional groups. The chemical agent which effectuates the crosslinking is selected based on the type of crosslinkable functional group(s) included in the polyolefin resin; a diverse array of reactions are known which crosslink crosslinkable functional groups via intermolecular and intramolecular chemical bonds. A suitable chemical agent is selected which is known to crosslink the crosslinkable functional groups present in the fabricated article to produce the crosslinked fabricated article. For example, without limiting the present disclosure, if the crosslinkable functional group attached to the polyolefin is a vinyl group, suitable chemical agents include free radical initiators such as peroxides or azo-bis nitriles, for example, dicumyl peroxide, dibenzoyl peroxide, t-butyl peroctoate, azobisisobutyronitrile, and the like. If the crosslinkable functional group attached to the polyolefin is an acid, such as a carboxylic acid, or an anhydride, or an ester, or a glycidoxy group, a suitable chemical agent can be a compound containing at least two nucleophilic groups, including dinucleophiles such as diamines, diols, dithiols, for example ethylenediamine, hexamethylenediamine, butane diol, or hexanedithiol. Compounds containing more than two nucleophilic groups, for example glycerol, sorbitol, or hexamethylene tetramine can also be used. Mixed di- or higher- nucleophiles, which contain at least two different nucleophilic groups, for example ethanolamine can also be suitable chemical agents. If the crosslinkable functional group attached to the polyolefin is a mono-, di- or tri- alkoxy silyl group, water, and Lewis or Bronsted acid or base catalysts can be used as suitable chemical agents. For example, without limiting the present disclosure, Lewis or Bronsted acid or base catalysts include aryl sulfonic acids, sulfuric acid, hydroxides, zirconium alkoxides or tin reagents.

[0017] Crosslinking the fabricated article is preferred to ensure that the fabricated article retains its shape at the elevated temperatures required for the subsequent processing steps. Without crosslinking, polyolefin resins typically soften, melt or otherwise deform or breakdown at elevated temperatures. Crosslinking adds thermal stability to the fabricated article.

[0018] The crosslinked fabricated article is heated in an oxidizing environment to yield a stabilized fabricated article. In some embodiments, the temperature for stabilizing the crosslinked fabricated article is at least 120 °C, preferably at least 190 °C. In some embodiments, the temperature for stabilizing the crosslinked fabricated article is no more than 400 °C, preferably no more than 300 °C. In one instance, the crosslinked fabricated article is introduced to a heating chamber which is already at the desired temperature. In another instance, the fabricated article is introduced to a heating chamber at or near ambient temperature, which chamber is subsequently heated to the desired temperature. In some embodiments the heating rate is at least 1 °C/minute. In other embodiments the heating rate is no more than 15 °C/minute. In yet another instance, the chamber is heated step wise, for instance, the chamber is heated to a first temperature for a time, such as, 120 °C for one hour, then is raised to a second temperature for a time, such as 180 °C for one hour, and third is raised to a holding temperature, such as 250 °C for 10 hours. The stabilization process involves holding the crosslinked fabricated article at the given temperature for periods up to 100 hours depending on the dimensions of the fabricated article. The stabilization process yields a treated stabilized fabricated article which is a precursor for a carbonaceous article. Without being limited by theory, the stabilization process oxidizes the crosslinked fabricated article and causes changes to the hydrocarbon structure that increases the crosslink density while decreasing the hydrogen/carbon ratio of the crosslinked fabricated article. Without being limited by theory, the stabilization process introduces either or both of phosphorous or nitrogen to the hydrocarbon structure.

[0019] Unexpectedly, it has been found that including a treating agent in the fabricated article during the stabilization step improves mass retention of the subsequently produced carbonaceous article. It has also been found that incorporating either or both of phosphorous or nitrogen in the crosslinked fabricated article improves form-retention of the subsequently produced carbonaceous article.

[0020] In another aspect, the present disclosure describes a treated stabilized fabricated article which is formed from a polyolefin precursor (resin). In one instance, the treated stabilized fabricated article is formed according to the process described herein.

[0021] In yet another aspect, a carbonaceous article and a process for making the same are provided. Carbonaceous articles are articles which are rich in carbon; carbon fibers, carbon sheets and carbon films are examples of carbonaceous articles. Carbonaceous articles have many applications, for example, carbon fibers are commonly used to reinforce composite materials, such as in carbon fiber reinforced epoxy composites, while carbon discs or pads are used for high performance braking systems.

[0022] The carbonaceous articles described herein are prepared by carbonizing the stabilized fabricated article by heat-treating the treated stabilized fabricated articles in an inert environment. The inert environment is an environment surrounding the treated stabilized fabricated article that shows little reactivity with carbon at elevated temperatures, preferably a high vacuum or an oxygen-depleted atmosphere, more preferably a nitrogen atmosphere or an argon atmosphere. It is understood that trace amounts of oxygen may be present in the inert atmosphere. In one instance, the temperature of the inert environment is at or above 600 °C. Preferably, the temperature of the inert environment is at or above 800 °C. In one instance, the temperature of the inert environment is no more than 3000 °C. In one instance, the temperature is from 1400-2400 °C. Temperatures at or near the upper end of that range will produce a graphite article, while temperatures at or near the lower end of the range will produce a carbon article.

[0023] In order to prevent bubbling or damage to the fabricated article during carbonization, it is preferred to heat the inert environment in a gradual or stepwise fashion. In one embodiment, the treated stabilized fabricated article is introduced to a heating chamber containing an inert environment at or near ambient temperature, which chamber is subsequently heated over a period of time to achieve the desired final temperature. The heating schedule can also include one or more hold steps for a prescribed period at the final temperature or an intermediate temperature or a programmed cooling rate before the article is removed from the chamber.

[0024] In yet another embodiment, the chamber containing the inert environment is subdivided into multiple zones, each maintained at a desired temperature by an appropriate control device, and the treated stabilized fabricated article is heated in a stepwise fashion by passage from one zone to the next via an appropriate transport mechanism, such as a motorized belt. In the instance where a treated stabilized fabricated article is a fiber, this transport mechanism can be the application of a traction force to the fiber at the exit of the carbonization process while the tension in the stabilized fiber is controlled at the inlet.

[0025] In one instance, the present disclosure describes a precursor polyolefin article comprising an empirical formula, CHWNXPYOZ, where: 1.8 < W < 2.2; 0.01 < X < 0.05 ; and 0.01 < Y < 0.04; and 0.04 < Z < 0.12. In one instance 2.0≤ W≤ 2.1. In one instance, 0.0167≤ X≤ 0.0314. In one instance, 0.0146 < Y < 0.0290. In one instance, 0.0595≤ Z≤ 0.0945.

[0026] In one instance, the present disclosure describes a stabilized polyolefin article comprising an empirical formula, CHwNxPyOz, where: 0.45≤ W≤ 0.85 ; 0.01≤ X≤ 0.035 ; 0.0005 < Y < 0.035; and 0.3≤ Z≤ 0.4. In one instance, 0.561≤ W≤ 0.776. In one instance, 0.0159≤ X≤ 0.0254. In one instance, 0.000975 < Y < 0.0282. In one instance, 0.326≤Z≤0.347.

[0027] In one instance, the present disclosure describes a carbonized polyolefin article comprising an empirical formula, CN _X P _Y , where: 0.005≤ X≤ 0.02; and 0.005 < Y < 0.025. In one instance, 0.00881≤ X≤ 0.0139. In one instance, 0.0100 < Y < 0.0176.

[0028] In one instance, it is observed that a stabilized fabricated article which has been treated as described herein (the treated stabilized article) has an increased mass yield as compared to a stabilized fabricated article which has not been treated as described herein during one or more of the fabrication steps (the control stabilized article). It has been observed that the control stabilized article has a mean oxidation mass yield of 36 percent, a mean carbonization mass yield of 30 percent, and a mean overall mass yield of 11 percent. It has been observed that the treated stabilized article has a mean oxidation mass yield of 52 to 76 percent, a mean carbonization mass yield of 53 to 57 percent, and a mean overall mass yield of 28 to 44 percent. It is observed that a stabilized fabricated article which has been treated with nitrogen and phosphorus realizes a 44 to 111 percent improvement in oxidation mass yield relative to the control stabilized article. It is observed that the stabilized fabricated article which has been treated with nitrogen and phosphorus realizes a 77 to 90 percent improvement in carbonization mass yield relative to the control stabilized article. It is observed that the stabilized fabricated article which has been treated with nitrogen and phosphorus realizes a 155 to 300 percent improvement in overall mass yield relative to the control stabilized article.

[0029] Some embodiments of the invention will now be described in detail in the following Examples.

[0030] In the Examples, overall mass yield is calculated as the product of oxidation mass yield and carbonization mass yield (calculated as provided below). PHR refers to parts per hundred resin (mass basis). MI refers to melt index which is a measure of melt flow rate. Wt% refers to parts per 100 total parts, mass basis. PE refers to polyethylene. Definitions of measured yields:

[0031] Oxidation mass yield: Y ₀ =—

mp _E

[0032] Carbonization mass yield: Y _c =

mox

[0033] Overall mass yield: Y _M = Y ₀ Y _C

[0034] Overall mass yield (carbonaceous mass per initial mass of PE): Y _{M PE} = ^Y ° ^Yc

^M %PE

[0035] Where mm is the initial mass of polyethylene; mox is the mass remaining after oxidation; mc _F is the mass remaining after carbonization; M%PE is the mass % of polyethylene in the origin formed article.

[0036] Soxhlet extraction is a method for determining the gel fraction and swell ratio of crosslinked ethylene plastics, also referred to herein as hot xylenes extraction. As used herein, Soxhlet extraction is conducted according to ASTM Standard D2765-11 "Standard Test Methods for Determination of Gel Content and Swell Ratio of Crosslinked Ethylene Plastics." In the method employed, a crosslinked fabricated article between 0.050 - 0.500 g is weighed and placed into a cellulose-based thimble which is then placed into a Soxhlet extraction apparatus with sufficient quantity of xylenes. Soxhlet extraction is then performed with refluxing xylenes for at least 12 hours. Following extraction, the thimbles are removed and the crosslinked fabricated article is dried in a vacuum oven at 80 °C for at least 12 hours and then weighed, thereby providing a Soxhlet-treated article. The gel fraction (%) is then calculated from the weight ratio (Soxhlet-treated article)/(crosslinked fabricated article). The TGA Method for determining percent stabilization by sulfonation is as follows: a TA Instruments Thermal Gravimetric Analyzer (TGA) Q5000 or Discovery Series TGA is used. Using ~ 10-20 mg for the analysis, the sample is heated at 10 °C/min to 800 °C under nitrogen. The final weight of the sample at 800 °C is referred to as the char yield. The VTMS content of the VTMS grafted resins was determined by 13C NMR.

[0037] The treated articles are submitted for elemental analysis to determine the carbon, hydrogen, nitrogen, sulfur, and oxygen content. A Thermo Model Flash EA1112

Combustion CHNS/O Analyzer is used for determining carbon, hydrogen, nitrogen, sulfur, and oxygen components. Phosphorus is detected by inductively coupled plasma atomic emission spectroscopy (ICP-AES) using a Perkin Elmer Optima 7300DV ICP atomic emission spectrometer.

[0038] Comparative Example 1

[0039] An ethylene/octene copolymer (density = 0.941 g/cm3; MI = 34 g/10 min,

190°C/2.16 kg) is melt blended with Esacure ONE, a commercially available photoinitiator sold by Lamberti, at 2 wt% (2.04 phr) at 180 °C in a Haake mixer under nitrogen. Films are compression molded using a Carver press at 180 °C into thin films measuring 2 mil (50.8 microns) thick by micrometer. All films are crosslinked (60 s exposure time per film side) using a 300 W/in H-type mercury UV lamp fitted with a parabolic (non-focused) reflector. The precursor films contain 85.3 wt% carbon and 13.9 wt% hydrogen by elemental analysis. See Tables 1-5. Five (5) smaller circular films are sectioned from the prepared films and weighed. The films are placed in a convection oven. The films are oxidized in the convection oven at 270 °C for 5 hours under air (21% oxygen content). Oxidized films are weighed. The mean elemental composition of the oxidized films is 69.6 wt% carbon, 6.0 wt% hydrogen, and 25.5 wt% oxygen. See Tables 6-10. Oxidized films are placed in a tube furnace and carbonized in an inert (nitrogen) environment to 1150°C at 4°C/min. The mean elemental composition of the carbonized films is 86.2 wt% carbon. See Tables 11-15. Carbonized films are weighed. Mean oxidation, carbonization, and overall mass yields of five (5) films are 36.1%, 30.3, and 10.9%, respectively.

Example 1A

[0040] An ethylene/octene copolymer (density = 0.941 g/cm3; MI = 34 g/10 min,

190°C/2.16 kg) is melt blended with Esacure ONE (a commercially available photoinitiator sold by Lamberti) at 2.04 phr and AP 423 (a commercially available ammonium

polyphosphate sold by Exolit) at 10.2 phr at 180 °C in a Haake mixer under nitrogen. Films are compression molded using a Carver press at 180 °C into thin films measuring 2 mil (50.8 microns) thick by micrometer. All films are crosslinked (60 s exposure time per film side) using a 300 W/in H-type mercury UV lamp fitted with a parabolic (non-focused) reflector. The precursor films contain 77.0 wt% carbon, 1.5 wt% nitrogen, 13.1 wt% hydrogen, 6.1 wt% oxygen, and 2.9 wt% phosphorus by elemental analysis. See Tables 1-5. Five (5) smaller circular films are sectioned from the prepared films and weighed. The films are placed in a convection oven. The films are oxidized in the convection oven at 270 °C for 5 hours under air (21% oxygen content). Oxidized films are weighed. The mean elemental composition of the oxidized films is 59.5 wt% carbon, 1.1 wt% nitrogen, 2.8 wt% hydrogen, 27.3 wt% oxygen, and 2.1 wt% phosphorus. See Tables 6-10. Oxidized films are placed in a tube furnace and carbonized in an inert (nitrogen) environment to 1150°C at 4°C/min. Carbonized films are weighed. The mean elemental composition of the carbonized films is 77.9 wt% carbon, 0.8 wt% nitrogen, and 2.8 wt% phosphorus. See Tables 11-15. Mean oxidation, carbonization, and overall mass yields are 67.3%, 56.8%, and 38.2%, respectively.

Example IB

[0041] An ethylene/octene copolymer (density = 0.941 g/cm3; MI = 34 g/10 min,

190°C/2.16 kg) is melt blended with Esacure ONE (a commercially available photoinitiator sold by Lamberti) at 2.04 phr and AP 423 (a commercially available ammonium

polyphosphate sold by Exolit) at 20.4 phr at 180 °C in a Haake mixer under nitrogen. Films are compression molded using a Carver press at 180 °C into thin films measuring 2 mil (50.8 microns) thick by micrometer. All films are crosslinked (60 s exposure time per film side) using a 300 W/in H-type mercury UV lamp fitted with a parabolic (non-focused) reflector. The precursor films contain 68.3 wt% carbon, 2.5 wt% nitrogen, 11.9 wt% hydrogen, 8.6 wt% oxygen, and 5.1 wt% phosphorus by elemental analysis. See Tables 1-5. Five (5) smaller circular films are sectioned from the prepared films and weighed. The films are placed in a convection oven. The films are oxidized in the convection oven at 270 °C for 5 hours under air (21% oxygen content). The mean elemental composition of the oxidized films is 57.5 wt% carbon, 1.7 wt% nitrogen, 3.3 wt% hydrogen, 26.6 wt% oxygen, and 4.2 wt% phosphorus. See Tables 6-10. Oxidized films are weighed. Oxidized films are placed in a tube furnace and carbonized in an inert (nitrogen) environment to 1150°C at 4°C/min. Carbonized films are weighed. The mean elemental composition of the carbonized films is 77.1 wt% carbon, 0.9 wt% nitrogen, and 3.5 wt% phosphorus. See Tables 11-15. Mean oxidation, carbonization, and overall mass yields are 76.4%, 57.2%, and 43.7%, respectively.

Example 1C

[0042] An ethylene/octene copolymer (density = 0.941 g/cm3; MI = 34 g/10 min,

190°C/2.16 kg) is melt blended with Esacure ONE (a commercially available photoinitiator sold by Lamberti) at 2.04 phr and AP 760 (a commercially available ammonium

polyphosphate sold by Exolit) at 10.2 phr at 180 °C in a Haake mixer under nitrogen. Films are compression molded using a Carver press at 180 °C into thin films measuring 2 mil (50.8 microns) thick by micrometer. All films are crosslinked (60 s exposure time per film side) using a 300 W/in H-type mercury UV lamp fitted with a parabolic (non-focused) reflector. Five (5) smaller circular films are sectioned from the prepared films and weighed. The films are placed in a convection oven. The films are oxidized in the convection oven at 270 °C for 5 hours under air (21% oxygen content). Oxidized films are weighed. The mean elemental composition of the oxidized films is 61.5 wt% carbon, 1.4 wt% nitrogen, 4.0 wt% hydrogen, 26.7 wt% oxygen, and 1.6 wt% phosphorus. See Tables 6-10. Oxidized films are placed in a tube furnace and carbonized in an inert (nitrogen) environment to 1150°C at 4°C/min. Carbonized films are weighed. Mean oxidation, carbonization, and overall mass yields are 52.3%, 53.3%, and 27.8%, respectively.

Example ID

[0043] An ethylene/octene copolymer (density = 0.941 g/cm3; MI = 34 g/10 min,

190°C/2.16 kg) is melt blended with Esacure ONE (a commercially available photoinitiator sold by Lamberti) at 2.04 phr and AP 760 (a commercially available ammonium

polyphosphate sold by Exolit) at 20.4 phr at 180 °C in a Haake mixer under nitrogen. Films are compression molded using a Carver press at 180 °C into thin films measuring 2 mil (50.8 microns) thick by micrometer. All films are crosslinked (60 s exposure time per film side) using a 300 W/in H-type mercury UV lamp fitted with a parabolic (non-focused) reflector. Five (5) smaller circular films are sectioned from the prepared films and weighed. The films are placed in a convection oven. The films are oxidized in the convection oven at 270 °C for 5 hours under air (21% oxygen content). Oxidized films are weighed. The mean elemental composition of the oxidized films is 57.7 wt% carbon, 2.0 wt% nitrogen, 3.6 wt% hydrogen, 26.4 wt% oxygen, and 3.2 wt% phosphorus. See Tables 6-10. Oxidized films are placed in a tube furnace and carbonized in an inert (nitrogen) environment to 1150°C at 4°C/min. Carbonized films are weighed. Mean oxidation, carbonization, and overall mass yields are 60.6%, 55.4%, and 33.5%, respectively.

Table 1

Precursor C (wt%) H (wt%) N (wt%) O (wt%) P (wt%)

Example

CI 85.3 13.9 0.0 0.0 0.0

1A 77.0 13.1 1.5 6.1 2.9

IB 68.3 11.9 2.5 8.6 5.1

Table 2

Precursor H/C (wt/wt) N/C (wt wt) O/C (wt/wt) N/H (wt/wt) P/C (wt/wt)

Example

CI 0.163 0.0 0.0 0.0 0.0

1A 0.170 0.0195 0.0792 0.115 0.0377

IB 0.174 0.0366 0.126 0.210 0.0747

Table 3

Precursor C (mol%) H (mol%) N (mol%) O (mol%) P (mol%)

Example

CI 34.0 66.0 0.0 0.0 0.0

1A 32.1 65.0 0.5 1.9 0.5

IB 30.9 64.3 1.0 2.9 0.9

Table 4

Precursor H/C N/C O/C N/H P/C

Example (mol/mol) (mol/mol) (mol/mol) (mol/mol) (mol/mol)

CI 1.94 0.0 0.0 0.0 0.0

1A 2.03 0.0167 0.0595 0.00823 0.0146

IB 2.08 0.0314 0.0945 0.0151 0.0290 Table 5

Table 6

Oxidized C (wt%) H (wt%) N (wt%) O (wt%) P (wt%)

Example

CI 69.6 6.0 0.0 25.5 0.0

1A 59.5 2.8 1.1 27.3 2.1

IB 57.5 3.3 1.7 26.6 4.2

1C 61.5 4.0 1.4 26.7 1.6

ID 57.7 3.6 2.0 26.4 3.2

Table 7

Oxidized H/C (wt/wt) N/C (wt/wt) O/C (wt wt) N/H (wt wt) P/C (wt wt)

Example

CI 0.0862 0.0 0.366 0.0 0.0

1A 0.0471 0.0185 0.459 0.393 0.0353

IB 0.0574 0.0296 0.463 0.515 0.0730

1C 0.0650 0.0228 0.434 0.350 0.0260

ID 0.0624 0.0347 0.458 0.556 0.0555

Table 8

Oxidized C (mol%) H (mol%) N (mol%) O (mol%) P (mol%)

Example

CI 43.4 44.6 0.0 11.9 0.0

1A 51.7 29.0 0.8 17.8 0.7

IB 48.0 32.8 1.2 16.7 1.4

1C 46.9 36.4 0.9 15.3 0.5

ID 46.8 34.8 1.4 16.1 1.0

Table 9

Oxidized H/C N/C O/C N/H P/C

Example (mol/mol) (mol/mol) (mol/mol) (mol/mol) (mol/mol)

CI 1.03 0.0 0.275 0.0 0.0

1A 0.561 0.0159 0.344 0.0282 0.0137

IB 0.685 0.0254 0.347 0.0370 0.0283

1C 0.776 0.0195 0.326 0.0252 0.0101

ID 0.744 0.0297 0.343 0.0399 0.0215 Table 10

Table 11

Carbonized C (wt%) N (wt%) P (wt%)

Example

CI 86.2 0.0 0.0

1A 77.9 0.8 2.8

IB 77.1 0.9 3.5

Table 12

Carbonized N/C (wt/wt) P/C (wt/wt)

Example

CI 0.0 0.0

1A 0.0195 0.0377

IB 0.0366 0.0747

Table 13

Carbonized C (mol%) N (mol%) P (mol%)

Example

CI 100.0 0.0 0.0

1A 97.8 0.9 0.5

IB 99.0 1.0 0.9

Table 14

Carbonized N/C P/C

Example (mol/mol) (mol/mol)

CI 0.0 0.0

1A 0.00881 0.0139

IB 0.0100 0.0176 Table 15